Bob was the firstborn of Olga and Victor Hansen, Danish immigrants to Canada. Bob's father died in 1957 from injuries suffered in the First World War.

It was from his father that Bob acquired his passion for science and nature, which later evolved into a concern for the environment. A self-proclaimed pessimist, Bob would say: "If we deliberately set about to destroy the planet, we couldn't do a better job than we are now."

His sense of humour was an antidote to his grim view of humanity. He was known for his imitation of a mute swan, for example. He would say that "time moves inexorably onward at the rate of one second per second," and that the world would be better off without the "infernal combustion engine." He got a charge out of reciting the word pneumonoultramicroscopicsilicovolcanoconiosis.

Bob tried to live Thoreau's philosophy that man is rich in proportion to the things he can afford to live without. In 1977, he had a moment of fame in a Toronto Star article about his homemade solar collector, which served the family's hot water needs in summer.

Bob trained in radio and Morse code in the early 1940s and traversed three oceans in the Canadian Merchant Navy during the Second World War. He was self-educated and regretted not having had the opportunity to attend university. His friend Bob Gunn says, "Bob was one of those gifted individuals who was able to learn about mathematics and science on his own. He could converse on subjects in calculus and science not usually known by the average citizen."

Bob's first job as a teenager was wrapping parcels in a department store. He helped support his family when his parents were unemployed and unwell. Siblings Peggy and Eric recall Bob paying each of them 25 cents a week, as well as paying board to his parents from his $6 weekly wage.

After a stint teaching in a vocational school, Bob worked as an electronics technician the rest of his life, retiring from York University in 1979.

In his youth, Bob had a following of neighbourhood boys with whom he explored the exciting world of science. They made their own percussion powder, packing it into cartridges that they placed on the streetcar tracks in Toronto. The operator would stop to inspect the streetcar while the boys hid, doubling over with laughter.

Bob met Helen Sinfield in 1954, offering her a peek through his binoculars at a Toronto Field Naturalists outing. They married in 1956. Bob was a loving and much loved husband to Helen for 56 years.

Bob lived a rich life with abundant hobbies. He loved astronomy, made his own telescopes, radios, stereos, coffee tables, bookcases and a playhouse for his daughters Anne and Jill. He was constantly buying and trading cameras and delivering family slide shows. His favourite botanical haunt was Ontario's Bruce Peninsula, legendary for its many orchid species.

Helen Hansen is Robert's wife.

Jill and Anne Hansen are his daughters.

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